By adding the greatest three-point shooter in the history of the league, it was expected that the Heat would go to a new level, given how successful they were in the NBA Finals by utilizing the long ball.
Yet, forgotten amid the fanfare of Allen's signing, was the detrimental impact his ageing body and declining athleticism would have on the team.
Of course the Heat would likely become a lethal team from behind the arc. However, by bringing in the former Celtic, the Heat would be relying on a 37-year-old guard with a bad ankle and declining athleticism to not only defend, but successfully operate from the perimeter in an athletically-dominated NBA.
Fast forward to today, and it's clear that the forgotten aspect in Allen's signing is hurting Miami more so than anyone would have believed.
The Ray Allen Effect
The generally held thought around the NBA is that the Heat's offense has taken off with Allen on board, while their defensive play has significantly slipped.
However, that presumption is wrong. Miami is a far better team when Allen sits on the bench.
This fact isn't just limited to one end of the court either.
Examine the chart below, which details the Heat's performance on the defensive end with Allen on and off the court.
With Allen on the court, Miami's defensive rating blows out as they concede five more points per 100 possessions. The team's rebounding performance also drops away, while the Heat's opposition score more efficiently when Allen is on the floor.
With a bad ankle and his legs deserting him, the veteran shooter can no longer keep up with opposition guards. Too easily, they are blowing past him and getting into the paint, which is resulting in baskets for either his direct opponent, or players left free from the subsequent defensive collapse.
The following clip is a good example of Allen's inability to defend his opponent.
Unable to keep his player in front of him, Allen has been forced to sit off his opponent. While this can prevent a defensive collapse, it has caused Miami all sorts of problems in their defense of the three-point line (ranked 22nd in the league for opponent three-point makes).
The following video is a good example of what happens when Allen chooses this approach. Watch the first, second and last threes hit by Wayne Ellington here.
To most NBA fans, these aren't exactly extraordinary revelations. After all, Allen wasn't brought in for his defense, was he?
However, he was brought in for his offense, and despite some impressive percentage numbers from deep, the 37-year-old's influence on the offensive end hasn't been a positive one for the team as a whole.
But he's shooting 49 percent from the field, 47 percent from three and 87 percent at the line, I hear you saying?
While his individual shooting numbers have been impressive, his impact on the team's offense as a whole has been far from desirable.
Examine the chart below, detailing the Heat's offensive performance with Allen on and off the court.
It's clearly evident that Miami is a better offensive team when Allen is on the bench. The Heat score seven more points per 100 possessions, and collectively shoot the ball better from the field and from deep when Allen is watching on from the sidelines.
Additionally, they distribute the ball more effectively, pull down more offensive rebounds and have a far superior plus/minus when Allen sits.
Although the numbers seem to go against logical trains of thought (considering Allen's shooting stats), Miami's better offensive production with the sharp shooter on the bench is a great example of the old adage "good defense leads to great offense."
With Allen's defensive struggles, the Heat are coming up with less stops when he's on the floor. Consequently, this leads to fewer transition opportunities and more half-court sets with the opposition's defense already in place.
These numbers certainly don't make for good reading for Allen on either end, at this stage in the season. However, it's unclear how this may pan out as the season draws on and heads into the playoffs.
Will the Heat find a way to cover Allen's deficiencies on defense? Will he continue to be a liability at that end? Or will his long-range shooting prowess prove to be critical in tight playoff games?
Given that he isn't getting any younger, it's unlikely we'll ever see him regain the athleticism required to be a solid NBA defender.
Yet teams have won championships with defensive liabilities before.
If the Heat can find a way to limit Allen's detrimental impact defensively, then it's possible that we may see this occur more often.
*All stats accurate as of Dec. 20.